SYNAPTIC INTEGRATION AND DEVELOPMENT IN COMMAND NEURONS

本研究将探讨突触的机制， 整合在外侧巨人（LG）的命令神经元，触发 发育期和成年期的小龙虾都能用后空翻逃脱。 两 问题将得到解决。 第一个问题是LG如何回应 对机械感觉输入的反应取决于紧张性和 阶段性机械感觉中间神经元（MSIs）的触觉刺激， LG上单个MSI的突触接触模式， LG的形态，以及被动和主动膜 LG的属性。这个问题将通过记录 两个确定的MSI的反应，一个相位和一个紧张， 机械感觉刺激，兴奋LG，通过识别可能的 MSI联系LG网站，并记录LG的回应 单独地和以各种模式。 结构、生物物理 突触反应数据将被用来重建 LG在定量模型中的综合特性， 细胞对正常输入模式的反应。 第二个问题是LG的综合性能如何 在动物从出生后的鱼苗到成年的生长过程中的变化， 以及这些变化和伴随的突触 LG的输入可以解释尾翻转行为的变化。 我们将 分析了LG在2cm、6cm和12cm的综合性能 动物在上述方式，并制定定量 以确定细胞中与生长相关的变化 形状、膜特性和突触输入应该影响LG。 我们还将确定数字发生了什么变化， LG从识别的MSI和从 一组机械感觉传入神经。 这项研究应确定 补偿机制允许不稳定的突触分离 在生长过程中保持活力，而非 不稳定的单突触通路失效。 由于神经元的生长 在所有的神经系统中， 在我们观察到的生长过程中 补偿这些变化可能被证明是共同的特点 神经系统的发展。

This research will investigate the mechanisms of synaptic integration in the lateral giant (LG) command neurons that trigger the escape tailflip of both developing and adult crayfish. Two questions will be addressed. The first asks how the LG's responses to mechanosensory inputs depend on the responses of tonic and phasic mechanosensory interneurons (MSIs) to tactile stimuli, the pattern of synaptic contact of individual MSIs on LG, the morphology of LG, and the passive and active membrane properties of LG. This question will be addressed by recording the responses of two identified MSIs, one phasic and one tonic, to mechanosensory stimuli that excite LG, by identifying possible MSI contact sites on LG and by recording LG's responses to them individually and in various patterns. The structural, biophysical and synaptic response data will be used to reconstruct the integrative properties of LG in a quantitative model that will acconut for the cell's responses to its normal patterns of input. The second question asks how the integrative properties of LG change during the animal's growth from post-natal fry to adult, and whether those changes and accompanying changes in synaptic inputs to LG can account for changes in tailflip behavior. We will analyse LG integrative properties in 2 cm, 6 cm and 12 cm animals in the manner described above, and develop quantitative models of them to determine how growth - related changes in cell shape, membrane properties and synaptic inputs should affect LG. We will also determine what changes occur in the number and pattern of inputs LG receives from identified MSIs and from the set of mechanosensory afferents. This study should identify the compensatory mechanisms that allow the labile disynaptic pathway to LG to remain viable during growth while the non- labile monosynaptic pathway fails. Since neuronal growth occurs in all nervous systems, both the changes in integrative properties during growth that we observe and the mechanisms that compensate for those changes may prove to be common features of developing nervous systems.